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What is a Sliding Sash Window?

Sliding sash windows have been a distinctive property feature since the 17th century and are still popular today. Also known as a vertical slider, sliding sash windows offer a mix of both authentic period aesthetics with modern engineering.


Although many have heard of the term ‘sash window’, the reasons behind the name and design may not be as well known. So, what is a sliding sash window? It’s basically a window that contains one or more moveable, sliding panels – ‘sashes’ – traditionally set inside a wooden window frame.

At JELD-WEN we offer a number of styles, colours and finishes. Depending on which style you go for, if only the upper sash is fixed, this is known as a single-hung sliding sash window. If both sashes are moveable, this is known as a double-hung sliding sash window.


The sash is the moveable part of the window, made up of the vertical and horizontal frame that holds the glass in place.


Instead of pushing the window open, like you would on a standard window, you can push sliding sash windows upwards. Due to this, you achieve a broader opening. It all works with the help of a modern spring balance. The tension in the spring assists in the lifting of the window, and holds the weight of the sash – so it can be easily operated.

One of the most important benefits of sliding sash windows is the airflow in and out of the property. On double-hung sash windows, by opening both to equal amounts the top sash allows warmer or ‘stale’ air to escape, whereas the bottom sash draws in cooler and cleaner air from outside. This probably isn’t a top priority for now, but during the summertime, you’ll be thankful for this feature.


Timber is a versatile and durable material, so it stands out from the crowd. Wood, by its very nature, is also a natural barrier to the cold. As all our sliding sash windows are made from timber, they provide a more renewable and sustainable option for your home. Timber is regarded as the better choice of material to offset carbon compared to other materials.

We are fully accredited by the FSC and PEFC, which certifies that our timber is sourced from responsible forestries. So, you can rest assured that your new sliding sash windows have been sourced in a highly ethical and sustainable way. Our timber windows are also manufactured in the UK by local quality craftsmen and women.


When we set out to design a sliding sash window, we knew we had to make something really special. Delivering lasting performance and timeless quality, their style has been designed specifically to match local planning and architectural requirements – meaning they’re the ideal choice for conservation areas too.

Manufactured to the highest standard, our sliding sash windows provide a traditional look with thermal performance and modern operation. Not only that, but our range is also fully weather stripped, features include stepped sashes for improved performance and a tilt in mechanism for easy cleaning and maintenance. Browse our full range and learn more, here.